According to the Data: Buy-Low Edition

Jonathan Bales is the author of the Fantasy Football for Smart People book series. In addition to RotoWire, Jonathan also provides content to the New York Times, Dallas Morning News, DallasCowboys.com, and NBC.

If you play the stock market, you know that the best time to sell is generally when everyone is highest on a stock. On the flip side, savvy investors look to buy when a stock's price is at its lowest point.

Fantasy football isn't only similar to a stock market, it is a stock market. Like a stock trader, your goal as an owner is to recognize where perceived value doesn't reflect actual value. Today, I'll take a look at a few "buy low" candidates-players whose actual value significantly exceeds their limited 2012 production.

Quarterbacks

Matthew Stafford, Detroit Lions
In my league, Stafford is ranked 21st among all quarterbacks - behind Andrew Luck, Mark Sanchez and Andy Dalton. No one thinks he'll remain that low as the season progresses, but most people are no longer buying Stafford as a top-five quarterback.

The Lions threw the ball more than any team in the NFL last year, however, and they'll probably do it again in 2012. Plus, Stafford is averaging just a hair under his 7.6 YPA from 2011, and we know his current 1:2 touchdown-to-interception ratio is going to improve.

Aaron Rodgers, Green Bay Packers
Don't panic on Rodgers. The Packers have played two really good defenses, and Rodgers should get Greg Jennings back this week. Rodgers won't match his astounding efficiency from 2011 (9.25 YPA), but he'll probably throw the ball more than 502 times. Plus, Rodgers will give you more on the ground moving forward, where he's rushed for only 21 yards and no touchdowns.

Tom Brady, New England Patriots
It might not seem like it, but Brady is on pace to set a career-high in attempts. His current YPA is lower than in any full season since 2006, so you know that will improve. It doesn't help that pass-catching tight end Aaron Hernandez will be out for a few weeks, but don't forget Brady owners know that as well. If they're panicking because of a perceived lack of weapons, be the owner to bring Brady aboard.

The fact that McFadden has given you No. 2 running back production after totaling only 54 yards and no touchdowns in the first two weeks should show you this guy's potential. Once he gets it going on the ground, which he will, he's a top-five back.

Doug Martin, Tampa Bay Bucs
While receivers can post quality fantasy numbers without receiving an abundance of looks, running backs need to have touches. Whether they come through the air or on the ground, touches are more important to owners than efficiency when it comes to running backs.

A big reason for that is the difference between an average running back and great running back in terms of YPC isn't even a full yard. A league-average back averages around 80 percent of the YPC as the league's top back, whereas a league-average receiver can sometimes total only half of the yards-per-reception as the NFL leader.

Martin hasn't been efficient through two weeks, averaging only 3.66 YPC. He has 44 carries, however, ranking him fourth in the NFL. The Bucs have made it clear Martin's workload won't decrease moving forward. As his YPC rises, so will his fantasy rank.

Wide Receivers

Julio Jones, Atlanta Falcons
You might be hard-pressed to find a fantasy owner willing to trade Jones, but a 14-yard receiving performance on Monday Night Football might boost those odds. Jones is still ranked 12th in PPR leagues following his poor showing against the Broncos. His 12.2 YPC will increase, and he's still on pace for 80 receptions. In the Falcons' up-tempo, no-huddle attack, there are plenty of balls to go around for both Jones and Roddy White.

A.J. Green, Cincinnati Bengals
Green is barely a No. 2 wide receiver even in PPR leagues, even with 12 receptions and a touchdown. The problem hasn't been opportunities; Green is fourth in the NFL with 23 targets. His catch rate of 52.2 percent is well below last year's mark, however, and even with the weak-armed Andy Dalton at quarterback, Green will improve upon his YPC (10.7) in a big way. Increased efficiency across the board is how wide receivers move up fantasy rankings.

Tight End

Brandon Pettigrew, Detroit Lions
I was so high on Pettigrew in the preseason I can't back down now. The primary reason I like the tight end is that, with defenses so focused on stopping Megatron, Pettigrew's targets are basically a sure thing. The return of Mikel LeShoure should actually help the Lions' passing game. Calvin Johnson will of course improve upon his numbers, but Pettigrew could really see a bump. He caught 70.9 percent of his targets in 2011, so you have to think his 57.4 percent catch rate thus far in 2012 will improve.